Lamp structure



Feb. 27, 1934. A, B SMWH I LAMP STRUCTURE Filed Jan. 2l, 1931 2 Sheets-Sheet l INVENVTOR zwem 0; M

Feb. 27, 41934. vA B, SMITH 1,948,806

LAMP STRUCTURE Filed Jan. 21, 1931 2 Sheets-Sheet 2 Patented Feb. 27, 1934 PATENT OFFICE UNITED STATES 8 Claims.

'I'he present invention relates broadly to the art of controlling electrical circuits, and more particularly to an improved article of manufacture in the form of a lamp, tube or equivalent means having incorporated therein as a part thereof suitable circuit controlling means, together with meansfor minimizing the sparking which is ordinarily attendant upon the making or breaking of an electrical circuit.

In my co-pending applications Serial Nos.

462,857 and 462,858, filed June 21, 1930, I have' disclosed and claimed improved lamp structures constituting unitary articles of manufacture and having included within the physical confines thereof means for making and breaking the lamp circuit under predetermined conditions.

The present application relates primarily, al-

though not exclusively, to structures of the general type disclosed in said applications, and has r for a particular object the provision of means also adapted to be located within the physical dimensions of such a structure-for minimizing the tendency of the circuit controlling means to arc or spark.

5 In the accompanying drawings I have shown for purposes of illustration only certain preierred embodiments of the present invention.

In the drawings Figure 1 is a view partly in elevation, partly in section, and partly broken away, illustrating one embodiment of my invention;

Figure 2 is a transverse sectional view on the line II-II of Figure 1;

Figure 3 is a vertical sectional view on the line III-III of Figure 2, looking in the direction of the arrows;

Figure 4 is a detail sectional view of a portion of a lamp structure illustrating a slightly modified embodiment ofthe invention;

40 Figure 5 is a view similar to Figure 1 illustrating still another embodiment of the invention;

Figure 5a is a view similar to Figure 5 showing a further modification of the invention;

Figure 6 is a viewA similar to Figures 1 and 5 showing another form of the invention; and

Figure 7 is a diagrammatic view which illustrates the effective circuit connections as applicable to any of. the forms of the invention herein disclosed.

" While the broad feature of applying a circuit controlling means to a lamp or similar article of manufacture, whether utilized for illuminating, display, advertising, radio transmission or reception or for other purposes, possesses advantages which will be apparent to those skilled in the art, such a construction is improved if means is provided for minimizing the arcing or sparking tendency occasioned by making and breaking the circuit. The present invention therefore is primarily concerned with the provision of such means, and more particularly where so incorporated with the other features as to provide a resulting structure adapted to be handled as a unit.

Referring more particularly to Figures 1, 2 and 65 3 of the drawings, there is indicated a lamp of the tungsten iilament type including a bulb 2 providing a filament chamber 3, the bulb being carried by a base 4 of any usual construction. As is customary in the art, the lamp includes a central stem assembly from which projects a tube or rod 6 having' a head 7, to which are secured anchor wires 8 cooperating with a filament 9 for maintaining the same in the desired position. One end of the filament is connected to4 a lead- 75 in wire 10 `extending through the tube assembly and extending therefrom so as to be secured in electrical connection with the base as indicated, for example, at 11. The opposite end of the niament is likewise connected to a lead-in wire 12 80 which is connected to a circuit making and breaking mechanism 14, in turn connected by a wire 15 to the contact 16 on the base 4. The circuit making and breaking structure, while capable of a large number of different embodiments is herein illustrated as comprising 'an insulating support 17 having an axial opening 18 therethrough adapted tobe slipped upwardly over the lower end of an exhaust tube 19 constituting part of the stem assembly. In this posi- 9 tion it lies primarily within the base 4 and within the physical dimensions of the lamp itself, but outside of or out of communication with the yniament chamber 3. Formed on the insulating support 17 is an extension 20 which carries a strip 21 preferably of bi-metallic or other thermostatlc metal. To the free end of this strip is secured a contact 22 adapted to cooperate with a second contact 23 secured to a projection 24 on the insulating support 17.

Surrounding the strip 21 is a winding of resistance wire 25, one end of the winding being secured to the strip 21 as indicated at 26, while the opposite end has already been described as the connection 15. The lead-in wire 12, before dem5 scribed, is shown as secured directly to the contact 23.

By reason of the construction just described, it will be apparent `that if the lamp is placed within a suitable circuit, current will now to the'lm filament in series with the make and break device. This current flow will continue until such time as the heat imparted by the winding 25 to the thermostatic strip 21 is suflicient to cause such strip to move the contact 22 out of engagement with the contact 23, and thus break the circuit.. This is more clearly indicated in Figure 7 in which the parts bear the reference characters utilized in connection with Figures 1, 2 and 3.

Upon separation of the contacts 22 and 23, the flow of current to the filament will be interrupted, the period of interruption continuing for an interval of time required to permit the strip .to cool to such an extent as to permit the contacts 22 and 23 to resume contacting position. This making and breaking of the circuit wil be periodically repeated at time intervals depending upon the initialtension placed on the strip 21. By means of a greater tension during the assembly operation, the interval can be made relatively longer, while by relatively less tension the interval can be reduced to such a brief period of time as to give a twinkle effect to the lamp.

Each making and breaking operation has a tendency to produce a spark between the contacts. While in many cases this sparking operation is not objectionable, there are many other cases in which it may either introduce a fire hazard, tend to break down the gases in the chamber in which the controlling means is located, or, as in the case of radio tubes, tend to produce an objectionable noise. The present invention provides means in combination with the parts already described for minimizing such sparking tendency. This means is herein illustrated as including a plate 27 of conducting material to which is connected a branch lead 28 in electrical connection with the lead 10.

In spaced relation to the plate 27 is a second conducting plate 29 to which is connected a branch lead 30 from the wire 15. The two plates are preferably located on opposite sides of a spacing material 31 and are preferably enclosed between outer and inner layers of insulation 32 and 33 respectively. While the plates and the insulation may be of any desired shape and size, they are preferably generally of the contour illustrated in Figure 2, whereby a circular or substantially circular condenser is provided, which con- -denser is shunted across the portion of the circuit which includes the make and break device. This construction not only provides a structure which may be readily incorporated within the physical confines of a lamp, thereby affording a compact assembly, but provides means eifective when the circuit is broken for absorbing a portion of the energy which is stored up in the condenser. Upon re-establishing the circuit the condenser tends to discharge into the circuit. There is thus provided a unitary article of manufacture including illuminating means, circuit controlling means and condensing means, all incorporated within the physical confines of a lamp or other article of manufacture.

From an inspection more particularly of Figure 2 of the drawings. it will be noted that the condenser may be built around or incorporated with the insulating support for the circuit controlling mechanism whereby the entire structure as a unit may be placed into position over the exhaust tube 19.

Wirth the construction just described it is necessary during the assembly operation to determine upon the time interval between iiashes by assembling the parts with a definite tension in the thermostatic strip. This construction is open to two possible objections. In the first place, it may happen that it is desired to subject the lamp to a burning in test, which is not possible with the circuit opening and closing very rapidly. In the second place it may be desirable to change the interval of flashing, and this is not possible with the construction disclosed.

In Figure 4 of the drawings there is illustrated a modified embodiment of the invention in which both of the objections referred to are obviated. In accordance with this embodiment, in which parts coresponding to parts already described are designated by the same reference characters having a prime affixed thereto, the base 4 is shown as being formed with a recess or depression 35 threaded to receive a screw 36 which is utilized in lieu of the contact 23. With this construction, the housing 24 of the form illustrated in Figure l, which was provided for the support of the Contact 23, is simply formed with an opening 37 through which the screw passes in such position as to be engaged by the contact 23. The screw maintains the parts in the desired relationship during the assembly of the base with the bulb, and thereafter enables such tension to be placed on the thermostatic strip that either a flashing or a burning in test is possible, and further enables the operator to adjust the tension at will subsequently to such test and thereby obtain any variation in the flashing interval which may be wished.

In Figure 5 there is illustrated a structure in which a circuit controlling mechanism is disposed within a sealed chamber 38, this chamber being conveniently formed in the stem 39 by the presses 40 and 41. Such a construction is described in my co-pending application Ser. No. 462,858, filed June 2l, 1930, before referred to. It differs principally from the construction just described in that the circuit making and breaking mechanism is sealed entirely Within a. separate chamber which, while gastight, may either be evacuated, filled with ordinary atmospheric air or with a special gas mixture. The condenser 42 previously described, while cooperating with the circuit controlling mechanism is located in a position preferably within the base.

In Figure 5a there is illustrated a structure generally similar to that illustrated in Figure 5, but differing therefrom in that the condenser 42' is also sealed within the stem between the presses 40' and 41. This modification illustrates the possibility of physically changing the location of the condenser as well as the location of the make and break device while still maintaining a unitary article of manufacture.

In Figure 6 there is illustrated another form of the invention, differing primarily from the forms previously described in that the circuit making and breaking mechanism 43 is inside oi or in communication with the filament chamber 44, thereby distinguishing from the previous structures in which, while the circuit controlling mechanism was physically within the limits of the lamp itself, it was outside of or out of communication with the filament chamber. In the form of Figure 6 also there is provided a condenser 45, preferably of the general construction before described, and located largely within the base 46 of the lamp.

With all forms of my invention herein illustrated and described, there is provided a unitary article of manufacture including illuminating means, circuit controlling means and condensing means. Such a combination of elements, and particularly when all are located within the physical dimensions of a unitary article so that merely by inserting that one article within a suitable circuit the advantages of all the individual parts are obtained.

Still other advantages arise from the provision more particularly of a lamp-like structure including condensing means in which the condensing means is so located with respect to the illuminating means as not to seriously interfere with the uniformity of the light intensity in the area illuminated thereby. It will be apparent for example that with the condenser located laterally of the filament, or otherwise in general proximity thereto, it will intercept some of the light rays and thereby cast a shadow within the illuminated area. While such a construction is within the scope of the present invention in cases where uniformity of light is not essential, I prefer other forms in which the condenser is located primarily within the base.

While I have herein illustrated and described certain preferred embodiments of the present invention, it will be understood that changes in the construction, operation and characteristics of the various parts herein illustrated and described may be made without departing either from the spirit of the invention or the scope of my broader claims.

I claim:

1. As an article of manufacture, a lamp including a stem assembly, a filament carried thereby, means positioned within the stem for exhausting the filament chamber, means carried by and embracing said stem for controlling the circuit to said filament, said means being ofthe heat responsive type, and condensing means for said circuit controlling means, said circuit controlling means and said condensing means together forming a unitary structure.

2. As an article of manufacture, a lamp. including a gas-tight filament chamber, a base, a

stem projecting from said base to said filament chamber, a filament on the end of said stem within the filament chamber, an exhaust tube within the stem and extending from the filament chamber to thebase, thermo-responsive means within the lamp assembly and accessible through said base for controlling the lamp circuit, condensing means in parallel with said circuitcontrolling means, saidthermo-responsive means and said condensing means forming a unitary structure, said base being provided with an opening to permit adjustment of said circuit controlling means while in position within the lamp assembly, which controlling means is coaxially arranged about said exhaust tube. l

3. In an electric lamp, a stem, a filament carried by said stem, thermo-responsive switch means carried by said stem for intermittently making and breaking the current to said filament, and a condenser carried by said stem bridged across the filament circuit, said switch means being in the filament circuit only, the condenser serving to reduce sparking in said switch upon the opening thereof.

4. As a new article of manufacture, a unitary lamp structure having a base and a bulb with a filament in the bulb, a thermally responsive switch supported by said structure and in series with the filament, and a condenser supported by said structure and connected in parallel with said filament and switch, said condenser serving to reduce sparking in said switch.

5. As a new article of manufacture, a unitary lamp structure having a base and a bulb with a filament in the bulb, a thermally responsive switch supported by said structure and in series with the filament, and a condenser supported by said structure and connected in parallel with said filament and switch, said condenser comprising concentrically disposed plates of cylindrical form positioned within said base.

6. In an electric lamp, a filament, a base having a sleeve portion and a base contact portion insulated from the sleeve portion, heat-responsive circuit making and breaking means within the lamp and in series with the filament, electrical connections between the filament and the base, and an electrical condenser connected between the sleeve portion and the base contact.

7. As an article of manufacture, a lamp including a stern assembly, a filament carried thereby, means positioned within the stem for exhausting the filament chamber, thermo-responsive means within the lamp in series with the filament and carried by the stem for intermittently making and breaking the circuit to said filament, and electrical condensing means carried by said stem and connected in parallel with the filament and thermo-responsive means, said condenser serving to reduce sparking when said thermo-responsive means operates.

8. As anvarticle of manufacture, a lamp including a base, a filament chamber, a filament therein, a stem support for said filament extending from the filament chamber to the base, adjustable thermo-responsive means within the 1 base carried by the stem support and accessible therethrough for making and breaking the current supply to the filament, an electrical condenser within said lamp connected in parallel with the filament and the thermo-responsive -30 

